Archivists at the Cornell Lab of Ornithology’s Macaulay Library spent a dozen years digitizing the nearly 150,000 analog audio recordings in its collection to put them on the Web. It’s lauded as an unequaled research and conservation resource.

"In terms of speed and the breadth of material now accessible to anyone in the world, this is really revolutionary," audio curator Greg Budney said in a news release announcing the archive.

The recordings date back to 1929. There’s an emphasis on birds, but sounds of everything from apes to zebras are also available.

The resource should prove a gold mine for researchers of many stripes, birders keen to fine-tune their identification skills, and many a parent answering inquisitive kids’ questions.

Going forward, the archivists aim to grow the collection with recordings from professional and amateurs alike.

"It’s just plain fun to listen to these sounds," Budney said. "Have you heard the sound of a walrus underwater? It’s an amazing sound."

John Roach is a contributing writer for NBC News. To learn more about him, check out his website.